Vacuum pump apparatus



y 3- F. H. ANDERSON I VACUUM PUMP APPARATUS Filed May 7, 19:55

Inventor:

r UJ v p m -em PUMP APPARATUS u l 1 Frederick-1H."Anderson, Schenectady,N. Yr,f assignor to General Electric-Company, a corpora-t tion of NewYork ci I Application May 7, 1935, SefiaPNoLfZDJSS' u e n 1 4 Claims.(01. fast-222') s A v I Myinventio'n relates tot vacuum pump apparelon.enbugh -to clear the pump chamber and n l jtus, particularlyt'ojroughing pump apparatus pump suctionpipe of all oilor foreign gases.At 2 operating inconnectionf with ahigh vacuum the-termination of thispredetermined time ina mercury condensation "pump for' evacuating tervalthe valve control means operated to close 5 mercury arc rectiflers orlike devices of the metal the relief valve, thereby cutting offtheconnec- 5 "tank type; andfit'sgeneral objectis to provide a tion ofthe pump suction pipeto atmosphere and} t yacuum pump apparatus of thischaracter which simultaneously'; to open the intake valve thereby is of*simplifledanddurable construction and of to connect the pump suctionpipe to the exhaust v increased eflicie'ncy'and reliability i'noperation. pipeline of the rectifier fornormalevacuationof A particularobject. of the invention is to prothe rectifier tank. I 10 a vide, forthe -vacuum pump apparatus, a valve My invention will be betterunderstood from the i means and automatically operated control meansfollowing descriptionwhen consideredin connectherefor'so' arranged thathigh starting 1 torque tion" with the accompanying drawing and its; tusually required in operation of the vacuum pump, scope will be pointedout in th'e appended claims; "ldand difficultlesgdue tofcreepa'ge of oilfrom the I Referring f to" the drawing; the" single? figure pumpintocoritactwith valve members'ordue to thereof is a semi-diagrammaticcross; sectional l jcreepage f oilinto the vacuum chamber of the "viewof a vacujum pumpjmechanism 'fori'an iron rectifier or likeldevice; areobviated. tarikr'ectifir or thelike, inflwhich'my invention i' [The'pump'apparatus'inwhich my present inhas been embodied. t gdyen'tion hasbeen embodied preferably includes an In the fi u e, the'lnumeral'ldesignates a" verelectrically drivenfpump mechanism which is esticallymounted rotary xhaust pumpdriven by" 'sentially similar to pumpmechanismsheretofore an electric motor 2. The pump and"motor' are;utilized as foompressors' forrefrigerator. apparaenclosed in a casing 3normally filled witli oil to "'tus. This pump" mechanism is preferablyversuch a heightjtha't the'pump is totallysubmerged 5 ticallymountedgthrotary pump itselfbeing subin the oil bath to prevent'air or othergas'esfrom s merged in an oil bath, in asubstantially sealed ente'ringthe pumpandto seal the pump. Excontairier and being" driven by an electric motorhaust gas'es'l from the rectifier enter the pump ;mounted in thecontainer'and aboveltherotary through a pumpjsuction pipe 4 andafteripasspump. y [s 'ingthrough' the pump and pump exhaust "valve 1 Inaccordancevwithmy inventionhin the.suc'-. .(not1fshown) into the casing3 escape to atmose 30 tion pipe leadingfroina point on the pump belowphere through an air port 5. 1 f I 1' *thefoilf level' to the exhaustpipeline of the The 'motor is supplied with current from' a" R grectifier is, mounted a combined intake valve ap' suitable currentsource; such as a "single phase paratus and relief'valyieapparatus, thecombined alternating current source, for example, con- 7 naipparatusbeing so arrangedand controlled that heated to supply lines 6,the current being conwhen the pump is brought to a stop, the intaketrolled for starting and running through suitable valve is closedand;siinultaneouslygthe rcliefkvalve motor t control means indicated bythe rectangle isopened to admit airnlat atmosphericpressure I, thecontrol means 'I being connect'e d'to the into thesuctionxpipeofthepurnp, h v motor by; leads 8 insulated from the'eover 9Thje i'elief valve remains open Whilethe pump-{by bushings'lfl. In orderto start and stop the 40 'standls idle,'therebydestroyingthevacuum inthe pump manually a switch means indicatedbyft he pump and pump suctionpipe'and' preventing all numeral II is providedin thesiipplylinesto thepossibility'of creeping ofoil or'oilvapor into conmptor. t n v v I v v itact with the intake valve and into the vacuum To control the connectionof the pump lt ofthe l 4 chamber of the rectifier. Upon-restarting ofthe exhaust line llwhich is connected to-the'lvacuum 45. pump theintakeyalve is held closed and'the chamber (not shown") "of a devicesuchas an iron 7 .7 relief valye is heldopenfor apredetermined time. tankrectifier, and to control the admission of 1 i inter-val to admit-Lairas above described to the airata'tmospheric pressure to the pump,a'con,' j pum'p'and pjump'suction pipe." This time interval trol'valveapparatus designated generally by the Y a c L 'isisuflieient'to permitthe pump to come up to 1 numeral 'l3;-is' connectedbetween the pump -sue50 1"normalwspeedi'unloaded; thereby eliminating the tion pipe Mand theexhaust line 12. The valve high star-tingtorque encounteredwhenthe pump,apparatus in the present embodiment'of thein-i is required to startagainst vacuum. The time vention is preferably constituted by a unitary215- a interval is extended'afterthe pump comes up' to sembly mounted onthe cover 9 of the pump cast- I 1 t 5 speed, fo'r'such 'a period thatthe" pump runsidle ing '3 and comprising a main valvemeans l'l formember 2|.

exhaust line I2, and a second valve means I5 to control the admission ofair at atmospheric pressure to the pump.

The main valve means I4 includes the upper open end of pump suction pipe4 and a valve disc I6 of rubber or other suitable material mounted in avalve foot I1 which is connected to the lower end of a valve stem I8.

The valve foot I1 is welded or otherwise fas-' tened in vacuum-tightrelation to the lower end of a bellows or sylphon valve member I9 whichis provided to give flexibility to the movement of the valve stem I8 andto seal off the valve means I4 from atmospheric pressure. The bellowsI9, valve foot I1 with its rubber disc I6, the upper end of pump suctionpipe 4, and the lower portion of valve stem I8 are enclosed within avacuum-tight casing 20 having a cover member 2|, the upper end ofbellows or sylphon member I9 being connected in vacuum-tight relation tocover A sleeve 22 for guiding the stern I8 projects downwardly fromcover 2|.

The second valve means, l5, includes a valve seat member 23 slidablymounted within a valveseat casing 24 and having in its lower face a:

valve disc 25 of rubber or other suitable material, and further includesthe upper end or tip 26 of .the valve stem I3, this upper portion of thestem being adapted to slide freely in the lower portion of valve seatcasing 24, into and out of contact with disc 25. The valve seat 23,together with its rubber disc 25, is biased downwardly toward the valvetip 26, by a spring 21 mounted in valve seat casing 24. Downward motionof the slidable seat 23 is limited by suitable stop means such as anoffset 28 in valve seat casing 24, and upward motion of seat 23 and itsdisc 25 is also limited by a stop means, such as a downwardly extendingportion 29 of aplug 30 which retains spring 21 within valve seat casing24.

To mount the valve seat 23 and its disc 25 of the valve means I5 inproper alignment with stem I8 and to provide a support for means toactuate the valve mechanism, a supporting and mounting member 3| isprovided preferably constituted by a casing member so arranged that theinterior of the casingisat atmospheric pressure. The support or casing 3is preferably mounted on the cover 2| of the vacuum-tight valve casing20.

To admit air at atmospheric pressure through the upper valve means I5into the pump suction pipe 4 and the pump I, a hole 32 is provided invalve stem I8 extending longitudinally therethrough and registering witha hole 33 provided in valve foot I1 and rubber disc I6 of the lower orintake valve means i4.

To operate the valve mechanisms I4 and I5 an electrical actuating meansis preferably provided which inthe present embodiment of the inventioncomprises a solenoid 34 having a plunger 35 which is connected as bysuitable link and lever mechanism, comprising, for example, two links 36and two levers 31, to valve stem I8, thelevers 31 being pivoted onthesupporting and mounting member 3|. The solenoid 34 is connected byleads 38 to the current supply line 6 through a switch means designatedby the numeral 39. Inv

through a thermostatic switch 43 having a heater element 44 to closecontacts 45 in one of the solenoid leads 38 and simultaneously toshortcircuit the heater 44 through contacts 46.

In operation of the apparatus above described, 7

upper side of valve foot I1, and relief valve I5 is open permitting airat atmospheric pressure to enter the upper end or tipv 26 of valve stemI8 and to flow through longitudinal hole 32 of stem I8 and hole 33 ofvalve foot I1 and valve disc I6 into the pump suction pipe 4 and thenceinto" pump I. After a predetermined period of time, for example 30seconds, the thermostatic element of switch 43 operates to short-circuititself, thereby to supply sufficient current'to actuating coil 4| ofrelay to close the contacts 45. The period of idle running of the motorvis sufficient to permit the clearing of all oil or foreigngases out ofthe pump before normal operation begins.

When contacts are closed by the relay coil 4| at the end of the timeinterval determined by thermostatic switch 43, current, is supplied tosolenoid 34 through leads 38; the plunger 35 is then drawn up therebylifting the valve stem I8 by an amount sufficient to open intake valveI4 by the lifting of rubber disc I6 away from the end of pipe I4, andsimultaneously to close relief valve I5 by the forcing of tip 26 ofvalve stem I8 into contact with rubber disc 25. The upward'motion ofvalve stem I8 is preferably such that valve seat 23, carrying disc25, isforced upward against the pressure of spring 21 into contact with stop29, the end of valve stem I8 then preferably continuing its upwardmotion for a short distance to dig slightly into the rubber disc 25 toinsure a vacuum-tight joint between the disc 25 and the tip v 26 of thevalve stem.

' of valve stem I8, the relief valve is caused to close and the 'intakevalve I4 is caused to open, the

pump. is now sealed from atmosphere and is connected to exhaust line I2for normal operation in exhausting the evacuated chamber of therectifier or other device to which exhaust line I2 is connected.

When the pump mechanism is .stopped, as by the manual opening of switchII, solenoid 34 is deenergizedplunger 35 drops to its lower positionillustrated in the drawing, and valve stem I 8' moves downwardly therebyreclosing intake valve I4 and reopening relief valve I5, the valve seat23 which carries rubber disc 25 being moved down, in contact with theupper end of the valve stem, by the pressure of spring 21 until thevalve seat 23 rests against the stop 28. When the pump is thus stoppedand theintake valve I4 is caused to close, air at atmospheric pressureis immediately admitted to the pump suction pipe 4 and pump I throughvalve I5 as hereinbefore described. Therefore the vacuum existing inthese parts of theapparatus is. destroyed and creepage of oil fromcasing 3 or from the pump into contact with rubber disc I6 of the intakevalve I4, or creepage of this oil past the valve I4 into connectedto'atmosphereriollow by the closing 1 oil of the valvebetwee and theopening or the;

' a I particiflarembodiment- 1 p I I us It is to be understoodfieifclrthuttl'ijefine ventlon ;is susceptible cv yai'ious changesiandmodifications and thkitlb thejappendedclaim's I .intend to coveranygsuch; b lflcations as iaii aiothinkthe truef'spirit and acopefiiof ,myinvenn r u m v i a in closed position and to exclude air to said pump,

the exhaust the n and {thence to thefevacuated chamber oi the rectifierDriOtheId2Y10e; is eflectuallyprevented.

' Upon furtherstarting pump the above described cycle of operations,including the period of idlerunning of. themotor- 1 v urpose's not;illustra My invention-has? between an exhaust line'and an exhaust pump,said 'valve' apparatus. including a hollow valve stem. valve means atone extremity of said stem'adapted. to open and to close the path fromsaid exhaust line to said pump, and a second valve means at theiothe'rextremity of u said stem operable simultaneously with said first-namedvalve means toIadmit air through.- saidste'm to said pump from outsidesaid ex-j' 'haust line whensaid tirst nameduvalve means is from outsidesaid exhaust line when said firstnamed valve means isin open position.

2. A control valve apparatus adapted to be interposed ,,between anexhaust lineand an exhaust pump, said valve apparatus including a hollowvalve stem, a valve casing: ands. valve supporting member, the interiorof said valve casing beingxat 'thepres'sure oi said line, the interiorof the valve supporting member bein 'at atmospheric pressure, .a valvemeans in said valve casing at one extremityhoi" said stem'to control theconncction'ol-said pump to said exhaust line, a valve means at the otherextremity of said-stem in said valvesupporting member to d. pping 1 ofthe I a t I ciaim,as:,ne' anddesire to secm'ty v1 vni iettersrPatent inthe United States is:

1 lm-A control valve apparatus-adapted to be 7 control the admission ofair at atmospheric presi sure to said'pump through said hollow stem andlmeans to operate said two valve'means simultaneously.

3..A unitary control valve apparatus adapted to be'interposed between anexhaust line and a vacuum pump; said valve apparatus comprise ingr tjjvalve stem having a'longitudinal aperture:- herethrough, an intakevalve between the pump- -anditheexhaust line including a valve discG021, fn'cte'd tome and of said valve stem and having an aperturetherethrougli registering-withsaid aperture of said stem, a relief valveopen to atmosphere and comprising the other end of saidj stemand' avalve disc adapted to close said aperture of said stem, and means tomove said valve stem'longitudinally toactuate said-intake and 1 reliefvalves, whereby said control valvelappa-y ratus is operable, to connectthe pump to the exhaust line and simultaneously to disconnect the pumpfromatmcsphere and operable there- 1 after to disconnect the pumpfrornvthe exhaust line and simultaneously to connect the'purnp'toatmosphere. H I 5 e g 4. A control valve apparatus adapted to beinterposed between an exhaust line and a vaca *"uum pump, said '7 valveapparatus comprising a valve stem, an intake valve between the pump 1and the exhaust line including a valve disc memj ber connected to anendof said stem, said-stem and 'saiddisc member being apertured to per,mit'the passage of air therethrough, a resilient vacuum-tight supportconnected to said disc member and surrounding said, end oi said stem.

a vacuum-tight casing surrounding said resil-- ient support, said discmember, and said end ot'said stem, said casing being connected tosaidexhaust line and to said pump, a relief valve, a relief valvesupporting member, said relief valve comprising the tip-oi the otherendof said stemand a valve disc 'slidably mounted take valve andsimultaneously to close said re-- lief valve. a

in said relief valve supporting member, and.

means to move said valve stem to open said -in-

